Are dogs with umbilical hernia deadly?

I have a dog and he is 4months old. he is feeling some pain so we brought him to the vet but the vet said he has hernia. since hee didn't tell us what kind of hernia he has I reaserched it and told my mom. My mom said it's umbilical. I read some articles about dogs with umbilical hernia and said it was deadly but still im not yet satisfied. Im so worried abt my dog. :( Please help :(